| Titanium and titanium alloys have been widely applied in the field of oral medicine because of the good physicochemical properties and excellent biocompatibility, but because of their higher modulus of elasticity, much larger than dental tissue and bone tissue, people have begun to focus on developing the titanium alloy with lower modulus of elasticity. Ti-24Nb-4Zr-7.9Sn alloy is a new type ofβ-titanium alloy, has a low modulus of elasticity, high strength at the same time. However, the biological activity of titanium and titanium alloys is poor and the combination of bone tissue is not close, at the same time, the physical conditions could easily lead to precipitation of metal ions. The solution to this problem is a way to modify the surface. This study uses micro-arc oxidation technology for TNZS alloy surface modification, and tests its physicochemical properties and biological safety on the modified micro-oxidation effects.ObjectiveTo detect the physicochemical properties and biological safety of TNZS alloy treated by micro-arc oxidation, explore the possibility of its clinical application and provide experimental basis for its clinical application in the future . Methods1. The TNZS alloy was treated by micro-arc oxidation with different voltage and frequency. Observed the surface morphology by SEM and detected the thickness of oxide film to evaluate the impact of voltage and frequency and select the appropriate voltage and pulse frequency.2. The phase,elemental composition,microhardness,thickness,bonding force,surface energy and roughness of the coatings were characterized by XRD,XPS,microhardness meter,metallurgical microscope,scarification meter contact angle measuring instrument and surface roughness meter respectively.3. According to the GB and YY-T, MAO-TNZS was tested with the cytotoxicity test,in vitro hemolytic test,oral mucous membrane irritation test and acute general toxicity test to evaluate its biological safety.Results1. A celadon rough film was formed on the surface of TNZS alloy treated by micro-arc oxidation and holes of 1 ~ 5μm diameter were distributed evenly on the surface. With the voltage increases the aperture and the thickness increased correspondingly.2. The film was composed of Ti,Nb,Zr,Sn,O,Ca and P elements. XRD indicated the phases in the film were rutile phase and anatase phase TiO2. The hardness was 414HV, bonding force was 32N,surface energy was 62.9 mJ/m2 and roughness was 1.175μm. The surface energy and roughness of TNZS was increased after being micro-arc oxidized.3. The result of cytotoxicity test showed that the samples had no cytotoxicity. The result of in vitro hemolytic test showed that the hemolytic rates of all samples were lower than 5%. The result of oral mucous irritation test showed that all samples had no mucous membrane irritation. The result of acute general toxicity test showed that all samples had no acute general toxicity.ConclusionMicro-arc oxidation treatment can form a rough,porous,calcium-rich film on TNZS surface,enhance the surface energy and roughness. With the voltage increases the aperture and thickness of the film increase correspondingly. The new TNZS alloy after being micro-arc oxidized possesses good biological safety.
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